ada yang tau energi gelap itu sebenernya apa? pengaruhnya apa sama alam semesta secara keseluruhan?

materi gelap setahu saya itu yang tidak mudah di deteksi keberadaannya seperti black hole. tetapi black hole itu bisa dideteksi dari efek gravitasi yang ditimbulkan.

Kutip dari: exile_rstd pada Oktober 12, 2011, 03:30:12 PM
materi gelap setahu saya itu yang tidak mudah di deteksi keberadaannya seperti black hole. tetapi black hole itu bisa dideteksi dari efek gravitasi yang ditimbulkan.

materi gelap pun punya gravitasi, dan cara mendeteksinya pun sama dengan blackhole ...
hanya saja 'dense'nya memang beda dengan blackhole, tak sedahsyat blackhole, dan lagi materi gelap takkan 'menguap' seperti blackhole, itulah yang membedakan ...
yeah, walau tentu masih ada kemungkinan materi gelap itu andai memang ada, mungkin saja blackhole2 ...

untuk pertanyaan thread, materi gelap adalah materi hipotesis tambahan yang dibutuhkan untuk menjelaskan berbagai fenomena yang tak dapat dijelaskan andai yang ada cuma materi biasa ...
dan sifatnya dipercaya beda dengan materi biasa yang dapat dideteksi dengan cahaya, materi gelap tak memancarkan ataupun memantulkan cahaya, sehingga tak bisa dilihat dan dinamakan gelap ...
dan sampai saat ini masalah apa itu materi gelap sesungguhnya masih diperdebatkan ...

In physical cosmology, astronomy and celestial mechanics, dark energy is a hypothetical form of energy that permeates all of space and tends to accelerate the expansion of the universe.[1] Dark energy is the most accepted theory to explain observations since the 1990s that indicate that the universe is expanding at an accelerating rate. In the standard model of cosmology, dark energy currently accounts for 73% of the total mass-energy of the universe.[2]

Two proposed forms for dark energy are the cosmological constant, a constant energy density filling space homogeneously,[3] and scalar fields such as quintessence or moduli, dynamic quantities whose energy density can vary in time and space. Contributions from scalar fields that are constant in space are usually also included in the cosmological constant. The cosmological constant is physically equivalent to vacuum energy. Scalar fields which do change in space can be difficult to distinguish from a cosmological constant because the change may be extremely slow.

High-precision measurements of the expansion of the universe are required to understand how the expansion rate changes over time. In general relativity, the evolution of the expansion rate is parameterized by the cosmological equation of state (the relationship between temperature, pressure, and combined matter, energy, and vacuum energy density for any region of space). Measuring the equation of state for dark energy is one of the biggest efforts in observational cosmology today.

Adding the cosmological constant to cosmology's standard FLRW metric leads to the Lambda-CDM model, which has been referred to as the "standard model" of cosmology because of its precise agreement with observations. Dark energy has been used as a crucial ingredient in a recent attempt to formulate a cyclic model for the universe.[4]

A 2011 survey of more than 200,000 galaxies appears to confirm the existence of dark energy, although the exact physics behind it remains unknown.[5][6]